Heating unit control



Nov. 22, 1960 E. R. WOLTERS ,040

HEATING UNIT CONTROL Fil'ed Aug. 15, 1958 I K &

ATTQRNEY$ ted States HEATING UNIT CONTROL Everett R. Wolters, 1022 Oaklette Ave., Norfolk, Va.

Filed Aug. 15, 1958, Ser. No. 755,249

2 Claims. (Cl.'158--4) This invention is directed to heating unit controls, and more specifically to an appliance for automatically controlling the combustion of fuel within the fire pot of a space heater, or the like, and comprises a continuation-in-part of my co-pending application, Serial No. 740,361, filed June 6, 1958, and entitled Control For Heating Unit.

One object of the invention resides in the provision of a safety control of the general type having an improved construction and assembly over previously known devices of this character.

Another object is the provision of a heater control wherein gas under pressure is utilized to extinguish or smother the fire in the combustion chamber or fire pot of a space heater.

Numerous further objects and advantages will become more readily apparent from a consideration of the following specification, when read in conjunction with the annexed drawing, in which:

Figure 1 is a perspective view of the space heater mounted beneath a floor or the like, and employing a fire pot flame control means constructed and assembled in accordance with the teachings of this invention;

Figure 2 is a detail cross-sectional view of the heater assembly, flame control means and automatic valve control assembly therefor, taken substantially along the section line 2-2 of Figure 1, looking in the direction of the arrows;

Figure 3 is an enlarged, fragmentary detail crosssectional view of the nozzle to which extinguishing gas or flame control medium is introduced into the fire pot; and

Figure 4 is an enlarged fragmentary cross-sectional view of the nozzle, taken substantially along the horizontal plane of the section line 44 of Figure 3, looking in the direction of the arrows.

From the drawings, it will be seen that reference numeral denotes a space heater employing a control assembly constructed and assembled in accordance with the teachings of the present invention. The heater 10 has a main body portion 12 which includes a fire pot 13 having a substantially discoidal base 14 and an integrally formed, upright, cylindrical side wall 16. The main body portion 12 also has a dome shaped combustion chamber 18 secured to, or formed integrally with, the side wall 16 thereof. As seen in the drawing, the side wall 16 of the fire pot 13 is provided with a plurality of air supply openings 20 formed therein to permit the entrance of air or other combustion supporting media into the fire pot. Fuel is supplied into the fire pot 13 by conduit 22 leading from a fuel source reservoir 24 and terminating within the fire pot at a fuel supply nozzle 26, and the fuel is ignited by the contact thereof with a conventional electrical starter unit 28 set in a depressed portion 30 of the base 14.

The environment of a space heater 10 here consists of the floor 32 of a building having a heat distributing grating 34 therein and the heater 10 is secured in a plenum chamber 36 which is secured to the floor joist 38 subjacent the aforesaid grating. As seen in Figures 1 and 2, the openings 20 in the side 16 of the fire box are outside of the chamber 36 in order that air may be readily drawn the-rethrough. Products of combustion are exhausted to the ambient atmosphere through a conventional flue pipe 39 which connects at its inner end with the combustion chamber 18.

Proceeding now to a specific description of the control means assembly 40 which forms a primary means of accomplishing the objectives of this invention, it will be seen that a temperature responsive switch or thermostatic control 42 is secured within the plenum chamber 36 at a point in proximity to the combustion chamber 18. The switch 42 is connected by leads 44 in an elec trical circuit including a solenoid 46 and a source of EMF. The solenoid 46 is adapted to actuate a normally closed valve 50 having its inlet port connected with one end of a conduit 70, the other end of the conduit being connected with a flame extinguishing medium source 72. The discharge side of the valve 50 is connected with a pipe 54 having a flared outer end 56. A rotatable nut 58 is slidably positioned on the pipe 54 and is held thereon by the outwardly flared end 56 thereof. As best seen in Figures 3 and 4, the nut '58 is threadedly engageable on the outer end of a substantially ogive extinguishing nozzle 60. The nozzle 60 is threadedly secured to the wall 16, and is seen to extend into the fire pot 13 above the openings 20. An integrally formed tightening nut 62 is positioned aroundthe nozzle 69 at a point adjacent to but spaced from the outer end thereof and serves to limit the inward displacement of the aforesaid nozzle.

In the cross-sectional view of Figure 4, it is seen that the nozzle 60 has a longitudinal passageway 64 having an enlarged outer end conforming in size substantially to the passageway in the pipe 54, and that the inner end thereof tapers to a substantially reduced portion 66. The inner end of the nozzle 60 is provided with a semicircular difiusing ring 68. The diffusing ring 68 serves a purpose to be described more fully below.

The intake side of the valve 50 is connected with a pipe 70, as described above, which leads to a pressurized container 72 having a flame extinguishing medium therein and including control means 74 which are normally left in their open position after installing the container 72 in the system. The flame extinguishing medium may be selected from a number of gases all of which are held under pressure and possess the characteristic of having a specific gravity greater than air, are volatile and nonflammable, examples of such gases being carbon dioxide, and a fiuorochloromethane such as, for example, that sold under the registered trademark Freon.

In operation, the fuel supply conduit 22 is activated by any conventional control means (not shown) and combustible fuel is directed through the nozzle 26 on to the starter unit 28 whereby the fuel is ignited. The combustion supporting media for the flame is drawn into the fire pot through the openings 20 formed in the side wall 16. When the combustion chamber 18 surpasses a predetermined maximum optimum operating temperature, the thermostatic control 42 is activated which in turn energizes the solenoid circuit thereby causing the control valve 50 to move to its open position. The gas under pressure in the container 72 now flows through the pipe 70 and valve 50 into the pipe 54 and is sprayed into the fire pot 13 through the nozzle 60. As seen in Figure 4, the gas is diffused in various directions by the semi-circular tip 68 of the nozzle 60. The action of the gas is twofold in that it smothers the flame in the fire pot by efiectively blocking the entrance of further 3 combustion supporting media, through the openings 20,

' and secondly, the refrigerant quality of the gas lowers the temperature of the fuel to a point beneath its ignition temperature. The How of fuel from the conduit 22 is automatically out off by; anyiconventiona'l thermal responsive control means which is sensitive to the lack of fire in the fire pot to prevent fres ultant flooding thereof.

When the unit has cooled to a predetermined low temperature, the thermostatic control switch 42- is auto matically opened to energize the circuit to the solenoid thus closing the valve 50 and shutting off the gas supplied therethrough. The gas is self-evaporating, and the fuel in the fire pot is re-ignited by the ignition unit 28.

Having described and illustrated indetail oneembodi- 'ment of this invention, it will be nnderstoodgthat the,

same is offered merely by way of example, and that this invention is to be limited only by the scope of the appended claims.

What is claimed is:

1. In a space heater having a main body portion including a dome shaped combustion chamber and sub-' jacent fire pot having a plurality of air supply openings formed therein; a plenum chamber enclosing said combustion chamber, a thermostatic control means and a sensing element disposed in said plenum chamber adjacent said combustion chamber, said control means including an electrical circuit adapted to energize a solenoid, to operate a valve in response to. a predetermined excessive temperature in said plenum chamber, said valve being connected with a source of gas under pressure, said gas comprising a member of the class of gases known as fluorochloromethanes, said thermostatic control means being operable in response to said excessive temperature to actuate said solenoid to open said valve and to permit said gas to flow through said valve and into said fire pot to extinguish the flame in said fire pot, and said thermostatic control means upon cooling of said plenum chamber below said predetermined temperature being operable in said circuit to tie-energize the latter and close said valve to cut oflr the supply of gas to said fire pot.

2. In a space heater including a main body portion,

1 a dome shaped combustion chamber, a subjacent fire pot having a plurality of openings extending transversely therethrough to admit a combustion supporting medium therein, a plenum chamber surrounding said combustion chamber, means extending through said fire pot above said openings for introducing a nonflammable gas into said fire pot to the exclusion of said combustion supporting medium, and internally sealing said openings, said last named means being operable only as a consequence of the presence of a temperature in said plenum chamber above a predetermined degree, and means for venting said combustion chamber to the atmosphere through said plenum chamber without mixing the products of combustion with the air in said plenum chamber.

References Cited in the file of this patent UNITED STATES. PATENTS Rotival Dec. 31,

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